Today, Apple began sending out invitations for its next big event, where the company is expected to announce a trio of new iPhones, an Apple Watch Series 3 with a cellular variant, and an Apple TV that supports 4K and HDR. In a final effort to get its software ready, the firm has released the ninth developer betas of both iOS 11 and tvOS 11.
iOS 11 still contains some known issues, but most of them have been fixed by now. Some third-party apps, such as Audiobus 3, MobileIron's Mobile@Work, Tweetbot, and Square Cash may not work properly, and presumably, at this point, it's on the developers to fix those. Most of the other known issues aren't front-facing.
tvOS 11 still has issues with Sling TV and FoxNow, along with known issues for CloudKit, Foundation, and Vision Framework. There aren't many new features coming to the OS, so it should be pretty stable.
It's rare that Apple ever actually releases a ninth beta, so it's fair to assume that these will be the last ones. After the company's event on the 12th, it will release GM seeds of iOS 11, macOS 10.13 High Sierra, watchOS 4, and tvOS 11, followed by a public release a couple of weeks later.